Sequence Enumeration

[ritchje]

Description

Sequence enumeration does not work.

Steps to Reproduce

[1,...,10] = Error 2034: Unexpected token in expression: ... in 'DEFAULT' (console) at line 1:4

Versions

Version: 2.5.2
Build date: 2017 Sep 11 10:27 CEST
Git commit description: Release/2.5.2.

[peterwvj]

Ranges currently only work for sets:

{1,...,10} = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

So it's not a bug. You could do:

[i | i in set{1,...,10}] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Does that help?

[peterwvj]

If order is important, you could define a function like this:

functions
seqRange: int * int -> seq of int
seqRange(f,t) ==
if f > t then []
else [f] ^ seqRange(f+1,t);

[nickbattle]

PJ is right, there is no such thing as a sequence range. But I've often wondered why not, given that set ranges exist. They would be very useful sometimes.

You could submit a request for a language extension to the Language Board? But it would take a while to get approved/implemented.

[ritchje]

@peterwvj @nickbattle Page 63 of the VDM manual mentions sequence enumeration? Maybe I've misinterpreted it?

[peterwvj]

Sequence enumerations are just sequence constructors, e.g. {1,2,3}. So it's not a range